Multicontact plug



K. J. BRAUN v MULTICONTAOT PLUG Filed May 20, 1937 2 Sheets-Sheet 1 Minna HIS M 19-, .1938; K. .1. BMW Z M MULTIGONTACT'PLUG Filed llay 20, 1937 2 Sheets-Sheet 2 F l G. 4

INVENTOR KARL J.BRAUN ATTORNEY Patented i 19, 1938 w 2,124,182

UNITED STATES PATENT OFFICE 2,124,182 mmrroon'mcr PLUG Karl J. Braun, Ridgewood, N. Y., assignor to Remington Rand Inc., Buii'alo, N. Y., a corporation of Delaware Application May 20, 1937, Serial No. 143,646

3 Claims. (01. 173-328) I This invention relates to multi-contact plugs, plug in which the contact fingers are easily and and particularly to the method of constructing quickly removable, so as to facilitate replacement. and assembling them. Other objects and structural details of the in- Previous to the present invention multi-contact vention will be apparent from the following de-- plugs were used in connection with Powers scription when read in connection with the ac- 5 punches, as is shown in Fig. 1 of the copending companying drawings in which: V application Serial No. 635,186. These plugs, how- Fig. 1 is an elevation of the plug showing it ever, were very cumbersome and inconvenient to completely assembled, but with some of the conuse, and were very expensive to manufacture. tact fingers left out for the sake of clearness;

They required quite some adjusting and were Fig. 2 is a vertical cross-section taken along 1o very heavy. The best plugs which were previousthe line 2-2 01 Fig. 1, and showing the two parts ly available had many disadvantages, in that they of the plug spaced slightly apart; were constructed of a seriesof stepped insulating Fig. 3 is a vertical cross section of the outer tubes, which tubes were nested one within the shell showing the three parts spaced slightly 1:; other. Spaced about the surfaces of these infrom one another; sulating tubes were a number of contact fingers Fig. 4 is an elevational detail view of the inwhich were very heavy. 'Each contact finger was sulating assemblies in the plug, and showing the fastened to its tube by two countersunk screws, positions of opposing contact fingers in relation and the fingers had to be made so heavy that to each other;

only a limited number could be screwed to each Fig. 5 is a front elevational detail of one of the 20 tube. Hence, while the fingers on any one tube contact fingers; were identical, they were diilerent in length than Fig. 6 is a side elevation. of-one of the contact the fingers on any other tube, so that several fingers; different kinds of fingers were necessary, All the Fig. 7 is a detail elevation of the male center insulating tubes were held together by an insucontact piece; w v 25 lating pin, and it was very difficult to disassemble Fig. 8 is an isometric view 'of one of the shell one of these plugs when a contact needed relatches;

' placing. Due to the heaviness of the assembly, Fig. 9 is a complete assembly elevational view it was necessary to screw one part of the plug of one set of contacts;

80 to the punch-frame, whereas the present plug Fig. 10 is a top plan view of one of the contact permits of a driving fit. finger retaining discs.

' The present invention is a multi-contact plug As will be seen from Figs. 1, 2, and 3, the plug which is very light and which provides wiping has an outer casing or shell which, in the present contacts throughout. Its shell is made, generally embodiment, is made in three pieces I, 2, and I speaking, in two parts. Each part contains a respectively; This outer casing is m y 35 pair of insulating discs which may be moulded to suitable strong material such as steel, etc., so that receive contact fingers. The contact fingers in it can withstand jarring and other heavy usages. the present invention are all alike, and may. be The p 3 is made with a Shoulder and t made of very light material, and they are formed. shoulder 4 is driven tigh y i 8 r me Wall 5 40 with centrally located shoulders. These shoulof any machine p which th -plug is to be 40 ders fit into the insulating rings which look the mounted. The shell piece 3 is also cut with a fingers in place, and keep the contact fingers gr v 5 to e v e lower D the pi from moving after assembly. A pair of spring A pin I protrudes ward y f o the grOOVe pressed latches, pivoted on the outside of one part and cooperates with a slot 8 on the shell piece 2 of the shell, coact with a pair of shouldered screws 80 s o p h tube 2 r turning wh n it i 45 on. the other part of the shell to hold the plug ineengagement with the piece 3, and to enforce together when it is in use. Iproper alignment of the contacts in bringing One object of the present invention is to propieces 2 and 3 together. The top piece I, in the vide a multi-contact plug which is light and present instance, is formed to give a close driving durable. fit in the piece 2, so that once it is driven in, it 50 Another object is to produce a plug in which will remain due to friction only. It will, however, the contact fingers are all identical. be seen that the pieces I and 2 could be made as a A third object is to produce a plug which is single piece and that, in substance. they are easily disassembled. just that.

Another object is to produce a multi contact Fig. 1 shows the plug completely assembled and mounted as it is in actual use. Here it will be seen that the shell pieces 2 and 3 are locked together by a pair or latches 9, only one of which is shown in this figure. The latches 9 are pivotally mounted byshouldered screws I0 upon opposite sides of the shell piece 3. As is most easily seen from Fig. 8, the latches 9 are formed with hooks II, and are provided with fingerpieces I2. Returning to Fig. 1, it is seen that the hooks II cooperate with shouldered screws IIIA to lock the shell pieces 2 and 3 together. Springs I3 tend constantly to press the latches 9 counterclockwise, as seen in Fig. 1, into locking position. To remove shell piece 2 from shell piece 3, it is only necessary to press the finger-pieces I2 clockwise, and then pull out the shell piece 2.

Referring particularly to Figs. 2, 4 to 7, 9, and 10, it is seen that each of the shell pieces 2 and 3 contains a contact unit 'which consists of a pair of insulating discs I4, an insulating collar I5, a plurality of contact fingers I6, and a center contact member I'I or "A, the contact I! being a male contact, and the contact I Hi being a female contact. The members I] and HA are threaded at one end and run through the centers of the insulating discs. Nuts I8 hold the assemblies together, so that they may be inserted as units into their respective shell pieces. As is most clearly shown in Fig. 4, the center contact members ii and "A are formed so that one fits into the other thus giving a wiping contact.

The contact fingers I6 are made of any suitable springy metal which is a good conductor of electricity. In the present instance they are made of beryllium copper. Each contact finger is the same size and shape as any other, and thus it is seen that they may very conveniently be diestamped at very low cost. Referring particularly to Figs. 5, 6, and 10, it is seen that each finger I6 is formed with slight extrusions I9 near its middle, and it will also be seen that the insulating discs I4 are moulded to receive these extrusions. The parts are so formed, that when they are assembled the insulating discs I4 engage the shoulders and hold the fingers I6 firmly in place.

As is seen in Fig. 2, the contact units are held in their respective shell pieces by means of screws. The screws I0 and IA, previously mentioned, are threaded into two of the discs I4, and short screws 20 and 20A are threaded into the remaining discs. The insulating collars I5 are here used merely to space the inner fingers I6 from the center contacts I! and "A.

Should any of the contact fingers I6 become damaged, it is only necessary to remove the'contact unit from its shell, remove the nut I8, and pull the discs I 4 apart. The damaged fingers can then be removed and new ones inserted.

Due to the fact that bent ends of the contact fingers in one shell piece point inward, while those in the other shell piece point outward, a wiping contact is made every time the shell piece 2 is plugged into the piece 3. As is well known, this type of contact is' self cleaning, and is\considered the best type of electrical contact now known for plugs.

While I have described what I consider to be a highly desirable embodiment of my invention, it is obvious that many changes in form could be madewithout departing from the spirit of my invention, and I, therefore, do not limit myself to the exact form herein shown and described, nor to anything less than the whole of my invention as hereinbefore set forth, and as hereinafter claimed.

What I consider new, and desire to secure by Letters Patent, is:

1. A multi-contact plug comprising a pair of shell members, a pair of spring-pressed latches carried by said shell members for latching said shell members together; and a pair of contact units, one for each shell member, secured in said shell members; each contact unit comprising a plurality of identical one-piece springy contact fingers formed with centrally located shoulders, a pair of-contact insulating and retaining discs each formed with a plurality of countersunk holes arranged in rings about the center thereof for holding said contact fingers, an insulating collar for preventing short circuiting, and a centrally located contact for securing together the insulating pieces of said contact unit.

2. A contact unit for electrical plugs including a plurality of fiat single-piece removable springy contact fingers formed with a pair of centrally located shoulders all of said contact fingers being identical in shape and size, a pair of identical contact insulating and retaining members each formed with a plurality of holes arranged in rings about the center thereofi'each hole being formed with a pair of countersunk shoulders for receiving and retaining one of said removable contact fingers, an insulating collar for preventing short circuiting, and a centrally located contact member havinga threaded shank and a cooperating nut for locking together the insulating members sunk holes arranged in rings about the center thereof adapted to hold said contact fingers therein with theends thereof extending beyond the outer faces of said discs, and a centrally located contact member having a threaded shank and a cooperating nut adapted to secure the members of said unit into an integral structure,

said centrally located contact member having a disc of insulating material positioned thereon to prevent short circuit between said central contact and the inner ring of said spring contacts.

KARL J. 

